Django の認証方法のカスタマイズ

デフォルトでdjangoに付属している認証方法は、極めて一般的なケースには十分ですが、あなたのニーズを満たされないケースがあるかもしれません。あなたのプロジェクトのニーズに合わせて認証方法をカスタマイズするには、提供されている認証システムはどのような点が拡張可能であるか、または交換可能であるかを理解する必要があります。本ドキュメントでは、認証システムをカスタマイズする方法の詳細を提供します。

認証バックエンド を利用すると、ユーザーモデルに保存されたユーザー名とパスワードを用いて異なるサービス間での認証を行う必要が生じた場合に Django 標準よりも高い拡張性を持たせることができます。

あなたはDjango認証システムを通した認証による改良したパーミッション<custom-permission>をあなたのユーザモデルに組み込むことができるでしょう。

あなたは標準の User モデルを 拡張、もしくは完全にカスタマイズしたモデルを 代わりに用いる 事ができます。

他の認証ソースを利用する

もしかしたらあなたは，他の認証元からユーザネームとパスワード，もしくは認証方式のため，別の認証元にhookする必要があるかもしれません。

例えばあなたの会社ですでに全ての従業員のユーザ名とパスワードを記録しているLDAP認証があるとしましょう。もしユーザがLDAP認証とdjangoアプリケーションで異なるアカウントだとしたらネットワーク管理者とユーザで口論になるでしょう。

そこでこのような状況に対応するためにDjangoの認証システムは他の認証システムのリソースと接続できます。あなたはDjangoのデフォルトのデータベーススキーマをオーバーライドするか、他のシステムを連携するためにデフォルトシステムを使うことができます。

Django に含まれている認証バックエンドに関する情報は 認証バックエンドリファレンス を参照してください。

認証バックエンドを指定する

内部的に、Django は認証を確認する「認証バックエンド」のリストを保持しています。django.contrib.auth.authenticate() を誰かがコールすると – どのようにログインするか で記述されているように – Django はその認証バックエンド全てに対して認証を試行します。最初の認証方法が失敗した場合、Django は次の方法、また次の方法といった具合に、全てのバックエンドに対して認証を試行します。

認証バックエンドとして利用するリストは AUTHENTICATION_BACKENDS に定義されています。この設定値は認証方法を定義している Python クラスを指定する Python パスのリスト型変数でなければなりません。これらのクラスはあなたの環境で有効な Python パスのどこにでも配置可能です。

初期状態では、AUTHENTICATION_BACKENDS は以下の値として定義されています。:

['django.contrib.auth.backends.ModelBackend']

これは Django のユーザーデータベースを確認してビルトインの権限を照会する基本的な認証バックエンドです。このバックエンドにはログイン試行を制限することでブルートフォース攻撃を防御する仕組みは提供していません。独自に試行制限を実装した認証バックエンドを利用するか、多くのウェブサーバーで提供されている各種防御機構が利用可能です。

AUTHENTICATION_BACKENDS への順番は処理に影響し、同じユーザー名とパスワードによって複数のバックエンドで有効な認証と判定されれば、Django は最初に有効と判定した時点で処理を終了します。

ある認証バックエンドにおいて PermissionDenied 例外が発生した場合、認証処理は直ちに終了し、Django は続く認証バックエンドに対する認証判定を行いません。

注釈

あるユーザーが一度認証されると、Django はそのユーザーの有効なセッション中はどの認証バックエンドがそのユーザーの認証に利用されたかを保持し、そのセッション有効期限中は認証されたユーザーの情報にアクセスする必要が生じる毎に同じ認証バックエンドを再利用します。これは認証情報がセッション毎に事実上キャッシュされる事を意味しており、従って AUTHENTICATION_BACKENDS を変更すると、ユーザーに対して異なる方法を用いた再認証を要求する際にはセッション情報を破棄する必要が有ります。これを実現する簡単な一つの方法は Session.objects.all().delete() をただ利用することです。

認証バックエンドの実装

認証バックエンドの実体は get_user(user_id) および authenticate(**credentials) という 2 つの必須メソッドとオプションの権限付与に関連した :ref:`認証メソッド <authorization_methods> のセットが実装されているクラスです。

get_user メソッドは user_id – ユーザー名、データベース上の ID 等何でも利用できますが、あなたが定義したユーザーオブジェクトの主キーである値 – を取って一つのユーザーオブジェクトを返します。

The authenticate method takes credentials as keyword arguments. Most of the time, it’ll just look like this:

class MyBackend(object):
    def authenticate(self, username=None, password=None):
        # Check the username/password and return a user.
        ...

But it could also authenticate a token, like so:

class MyBackend(object):
    def authenticate(self, token=None):
        # Check the token and return a user.
        ...

Either way, authenticate() should check the credentials it gets and return a user object that matches those credentials if the credentials are valid. If they’re not valid, it should return None.

The Django admin is tightly coupled to the Django User object. The best way to deal with this is to create a Django User object for each user that exists for your backend (e.g., in your LDAP directory, your external SQL database, etc.) You can either write a script to do this in advance, or your authenticate method can do it the first time a user logs in.

Here’s an example backend that authenticates against a username and password variable defined in your settings.py file and creates a Django User object the first time a user authenticates:

from django.conf import settings
from django.contrib.auth.hashers import check_password
from django.contrib.auth.models import User

class SettingsBackend(object):
    """
    Authenticate against the settings ADMIN_LOGIN and ADMIN_PASSWORD.

    Use the login name and a hash of the password. For example:

    ADMIN_LOGIN = 'admin'
    ADMIN_PASSWORD = 'pbkdf2_sha256$30000$Vo0VlMnkR4Bk$qEvtdyZRWTcOsCnI/oQ7fVOu1XAURIZYoOZ3iq8Dr4M='
    """

    def authenticate(self, username=None, password=None):
        login_valid = (settings.ADMIN_LOGIN == username)
        pwd_valid = check_password(password, settings.ADMIN_PASSWORD)
        if login_valid and pwd_valid:
            try:
                user = User.objects.get(username=username)
            except User.DoesNotExist:
                # Create a new user. There's no need to set a password
                # because only the password from settings.py is checked.
                user = User(username=username)
                user.is_staff = True
                user.is_superuser = True
                user.save()
            return user
        return None

    def get_user(self, user_id):
        try:
            return User.objects.get(pk=user_id)
        except User.DoesNotExist:
            return None

Handling authorization in custom backends

Custom auth backends can provide their own permissions.

The user model will delegate permission lookup functions (get_group_permissions(), get_all_permissions(), has_perm(), and has_module_perms()) to any authentication backend that implements these functions.

The permissions given to the user will be the superset of all permissions returned by all backends. That is, Django grants a permission to a user that any one backend grants.

If a backend raises a PermissionDenied exception in has_perm() or has_module_perms(), the authorization will immediately fail and Django won’t check the backends that follow.

The simple backend above could implement permissions for the magic admin fairly simply:

class SettingsBackend(object):
    ...
    def has_perm(self, user_obj, perm, obj=None):
        return user_obj.username == settings.ADMIN_LOGIN

This gives full permissions to the user granted access in the above example. Notice that in addition to the same arguments given to the associated django.contrib.auth.models.User functions, the backend auth functions all take the user object, which may be an anonymous user, as an argument.

A full authorization implementation can be found in the ModelBackend class in django/contrib/auth/backends.py, which is the default backend and queries the auth_permission table most of the time. If you wish to provide custom behavior for only part of the backend API, you can take advantage of Python inheritance and subclass ModelBackend instead of implementing the complete API in a custom backend.

Authorization for anonymous users

An anonymous user is one that is not authenticated i.e. they have provided no valid authentication details. However, that does not necessarily mean they are not authorized to do anything. At the most basic level, most websites authorize anonymous users to browse most of the site, and many allow anonymous posting of comments etc.

Django’s permission framework does not have a place to store permissions for anonymous users. However, the user object passed to an authentication backend may be an django.contrib.auth.models.AnonymousUser object, allowing the backend to specify custom authorization behavior for anonymous users. This is especially useful for the authors of re-usable apps, who can delegate all questions of authorization to the auth backend, rather than needing settings, for example, to control anonymous access.

Authorization for inactive users

An inactive user is one that has its is_active field set to False. The ModelBackend and RemoteUserBackend authentication backends prohibits these users from authenticating. If a custom user model doesn’t have an is_active field, all users will be allowed to authenticate.

You can use AllowAllUsersModelBackend or AllowAllUsersRemoteUserBackend if you want to allow inactive users to authenticate.

The support for anonymous users in the permission system allows for a scenario where anonymous users have permissions to do something while inactive authenticated users do not.

Do not forget to test for the is_active attribute of the user in your own backend permission methods.

Changed in Django 1.10:

In older versions, the ModelBackend allowed inactive users to authenticate.

Handling object permissions

Django’s permission framework has a foundation for object permissions, though there is no implementation for it in the core. That means that checking for object permissions will always return False or an empty list (depending on the check performed). An authentication backend will receive the keyword parameters obj and user_obj for each object related authorization method and can return the object level permission as appropriate.

Custom permissions

To create custom permissions for a given model object, use the permissions model Meta attribute.

This example Task model creates three custom permissions, i.e., actions users can or cannot do with Task instances, specific to your application:

class Task(models.Model):
    ...
    class Meta:
        permissions = (
            ("view_task", "Can see available tasks"),
            ("change_task_status", "Can change the status of tasks"),
            ("close_task", "Can remove a task by setting its status as closed"),
        )

The only thing this does is create those extra permissions when you run manage.py migrate (the function that creates permissions is connected to the post_migrate signal). Your code is in charge of checking the value of these permissions when a user is trying to access the functionality provided by the application (viewing tasks, changing the status of tasks, closing tasks.) Continuing the above example, the following checks if a user may view tasks:

user.has_perm('app.view_task')

Extending the existing User model

There are two ways to extend the default User model without substituting your own model. If the changes you need are purely behavioral, and don’t require any change to what is stored in the database, you can create a proxy model based on User. This allows for any of the features offered by proxy models including default ordering, custom managers, or custom model methods.

If you wish to store information related to User, you can use a OneToOneField to a model containing the fields for additional information. This one-to-one model is often called a profile model, as it might store non-auth related information about a site user. For example you might create an Employee model:

from django.contrib.auth.models import User

class Employee(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    department = models.CharField(max_length=100)

Assuming an existing Employee Fred Smith who has both a User and Employee model, you can access the related information using Django’s standard related model conventions:

>>> u = User.objects.get(username='fsmith')
>>> freds_department = u.employee.department

To add a profile model’s fields to the user page in the admin, define an InlineModelAdmin (for this example, we’ll use a StackedInline) in your app’s admin.py and add it to a UserAdmin class which is registered with the User class:

from django.contrib import admin
from django.contrib.auth.admin import UserAdmin as BaseUserAdmin
from django.contrib.auth.models import User

from my_user_profile_app.models import Employee

# Define an inline admin descriptor for Employee model
# which acts a bit like a singleton
class EmployeeInline(admin.StackedInline):
    model = Employee
    can_delete = False
    verbose_name_plural = 'employee'

# Define a new User admin
class UserAdmin(BaseUserAdmin):
    inlines = (EmployeeInline, )

# Re-register UserAdmin
admin.site.unregister(User)
admin.site.register(User, UserAdmin)

These profile models are not special in any way - they are just Django models that happen to have a one-to-one link with a user model. As such, they aren’t auto created when a user is created, but a django.db.models.signals.post_save could be used to create or update related models as appropriate.

Using related models results in additional queries or joins to retrieve the related data. Depending on your needs, a custom user model that includes the related fields may be your better option, however, existing relations to the default user model within your project’s apps may justify the extra database load.

Substituting a custom User model

Some kinds of projects may have authentication requirements for which Django’s built-in User model is not always appropriate. For instance, on some sites it makes more sense to use an email address as your identification token instead of a username.

Django allows you to override the default user model by providing a value for the AUTH_USER_MODEL setting that references a custom model:

AUTH_USER_MODEL = 'myapp.MyUser'

This dotted pair describes the name of the Django app (which must be in your INSTALLED_APPS), and the name of the Django model that you wish to use as your user model.

Using a custom user model when starting a project

If you’re starting a new project, it’s highly recommended to set up a custom user model, even if the default User model is sufficient for you. This model behaves identically to the default user model, but you’ll be able to customize it in the future if the need arises:

from django.contrib.auth.models import AbstractUser

class User(AbstractUser):
    pass

Don’t forget to point AUTH_USER_MODEL to it. Do this before creating any migrations or running manage.py migrate for the first time.

Changing to a custom user model mid-project

Changing AUTH_USER_MODEL after you’ve created database tables is significantly more difficult since it affects foreign keys and many-to-many relationships, for example.

This change can’t be done automatically and requires manually fixing your schema, moving your data from the old user table, and possibly manually reapplying some migrations. See #25313 for an outline of the steps.

Due to limitations of Django’s dynamic dependency feature for swappable models, the model referenced by AUTH_USER_MODEL must be created in the first migration of its app (usually called 0001_initial); otherwise, you’ll have dependency issues.

In addition, you may run into a CircularDependencyError when running your migrations as Django won’t be able to automatically break the dependency loop due to the dynamic dependency. If you see this error, you should break the loop by moving the models depended on by your user model into a second migration. (You can try making two normal models that have a ForeignKey to each other and seeing how makemigrations resolves that circular dependency if you want to see how it’s usually done.)

Reusable apps and AUTH_USER_MODEL

Reusable apps shouldn’t implement a custom user model. A project may use many apps, and two reusable apps that implemented a custom user model couldn’t be used together. If you need to store per user information in your app, use a ForeignKey or OneToOneField to settings.AUTH_USER_MODEL as described below.

User モデルを参照する

User を直接参照する場合 (例えば外部キーで参照する場合)、AUTH_USER_MODEL 設定が異なるユーザモデルに変更されたプロジェクトでは正しく動作しません。

get_user_model()[ソース]

User を直接参照する代わりに、django.contrib.auth.get_user_model() を使ってユーザモデルを参照すべきです。このメソッドは現在アクティブなユーザモデルを返します – 指定されている場合はカスタムのユーザモデル、指定されていない場合は User です。

ユーザモデルに対して外部キーや多対多の関係を定義するときは、AUTH_USER_MODEL 設定を使ってカスタムのモデルを指定してください。例えば:

from django.conf import settings
from django.db import models

class Article(models.Model):
    author = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
    )

ユーザモデルによって送信されたシグナルと接続するときは、AUTH_USER_MODEL 設定を使ってカスタムのユーザモデルを指定してください。例えば:

from django.conf import settings
from django.db.models.signals import post_save

def post_save_receiver(sender, instance, created, **kwargs):
    pass

post_save.connect(post_save_receiver, sender=settings.AUTH_USER_MODEL)

一般的に言って、コード内では AUTH_USER_MODEL 設定を使ってユーザモデルを参照すべきで、これは import のときに実行されます。get_user_model() は Django が全てのモデルをインポートし終わったときのみ動作します。

Specifying a custom user model

Model design considerations

Think carefully before handling information not directly related to authentication in your custom user model.

It may be better to store app-specific user information in a model that has a relation with the user model. That allows each app to specify its own user data requirements without risking conflicts with other apps. On the other hand, queries to retrieve this related information will involve a database join, which may have an effect on performance.

Django expects your custom user model to meet some minimum requirements.

1. If you use the default authentication backend, then your model must have a single unique field that can be used for identification purposes. This can be a username, an email address, or any other unique attribute. A non-unique username field is allowed if you use a custom authentication backend that can support it.
2. Your model must provide a way to address the user in a “short” and “long” form. The most common interpretation of this would be to use the user’s given name as the “short” identifier, and the user’s full name as the “long” identifier. However, there are no constraints on what these two methods return - if you want, they can return exactly the same value.

The easiest way to construct a compliant custom user model is to inherit from AbstractBaseUser. AbstractBaseUser provides the core implementation of a user model, including hashed passwords and tokenized password resets. You must then provide some key implementation details:

class models.CustomUser

USERNAME_FIELD

A string describing the name of the field on the user model that is used as the unique identifier. This will usually be a username of some kind, but it can also be an email address, or any other unique identifier. The field must be unique (i.e., have unique=True set in its definition), unless you use a custom authentication backend that can support non-unique usernames.

In the following example, the field identifier is used as the identifying field:

class MyUser(AbstractBaseUser):
    identifier = models.CharField(max_length=40, unique=True)
    ...
    USERNAME_FIELD = 'identifier'

USERNAME_FIELD now supports ForeignKeys. Since there is no way to pass model instances during the createsuperuser prompt, expect the user to enter the value of to_field value (the primary_key by default) of an existing instance.

REQUIRED_FIELDS

A list of the field names that will be prompted for when creating a user via the createsuperuser management command. The user will be prompted to supply a value for each of these fields. It must include any field for which blank is False or undefined and may include additional fields you want prompted for when a user is created interactively. REQUIRED_FIELDS has no effect in other parts of Django, like creating a user in the admin.

For example, here is the partial definition for a user model that defines two required fields - a date of birth and height:

class MyUser(AbstractBaseUser):
    ...
    date_of_birth = models.DateField()
    height = models.FloatField()
    ...
    REQUIRED_FIELDS = ['date_of_birth', 'height']

注釈

REQUIRED_FIELDS must contain all required fields on your user model, but should not contain the USERNAME_FIELD or password as these fields will always be prompted for.

REQUIRED_FIELDS now supports ForeignKeys. Since there is no way to pass model instances during the createsuperuser prompt, expect the user to enter the value of to_field value (the primary_key by default) of an existing instance.

is_active

A boolean attribute that indicates whether the user is considered “active”. This attribute is provided as an attribute on AbstractBaseUser defaulting to True. How you choose to implement it will depend on the details of your chosen auth backends. See the documentation of the is_active attribute on the built-in user model for details.

get_full_name()

A longer formal identifier for the user. A common interpretation would be the full name of the user, but it can be any string that identifies the user.

get_short_name()

A short, informal identifier for the user. A common interpretation would be the first name of the user, but it can be any string that identifies the user in an informal way. It may also return the same value as django.contrib.auth.models.User.get_full_name().

Importing AbstractBaseUser

New in Django 1.9.

AbstractBaseUser and BaseUserManager are importable from django.contrib.auth.base_user so that they can be imported without including django.contrib.auth in INSTALLED_APPS (this raised a deprecation warning in older versions and is no longer supported in Django 1.9).

The following attributes and methods are available on any subclass of AbstractBaseUser:

class models.AbstractBaseUser

get_username()

Returns the value of the field nominated by USERNAME_FIELD.

clean()

New in Django 1.10.

Normalizes the username by calling normalize_username(). If you override this method, be sure to call super() to retain the normalization.

classmethod normalize_username(username)

New in Django 1.10.

Applies NFKC Unicode normalization to usernames so that visually identical characters with different Unicode code points are considered identical.

is_authenticated

(AnonymousUser.is_authenticated が常に False なのとは対照的に) 常に True の読み取り専用属性です。ユーザが認証済みかどうかを知らせる方法です。これはパーミッションという意味ではなく、ユーザーがアクティブかどうか、また有効なセッションがあるかどうかをチェックするわけでもありません。 通常、request.user のこの属性をチェックして AuthenticationMiddleware (現在ログイン中のユーザを表します) によって格納されているかどうかを調べます。User のインスタンスの場合、この属性は True となります。

Changed in Django 1.10:

古いバージョンでは、メソッドでした。メソッドとして使うための後方互換性サポートは、Django 2.0 で廃止されます。

is_anonymous

Read-only attribute which is always False. This is a way of differentiating User and AnonymousUser objects. Generally, you should prefer using is_authenticated to this attribute.

Changed in Django 1.10:

古いバージョンでは、メソッドでした。メソッドとして使うための後方互換性サポートは、Django 2.0 で廃止されます。

set_password(raw_password)

Sets the user’s password to the given raw string, taking care of the password hashing. Doesn’t save the AbstractBaseUser object.

When the raw_password is None, the password will be set to an unusable password, as if set_unusable_password() were used.

check_password(raw_password)

与えられた生の文字列が、ユーザに対して正しいパスワードであれば True を返します。 (比較する際にはパスワードハッシュを処理します。)

set_unusable_password()

Marks the user as having no password set. This isn’t the same as having a blank string for a password. check_password() for this user will never return True. Doesn’t save the AbstractBaseUser object.

アプリケーションの認証が LDAP ディレクトリなどの既存の外部ソースに対して行われている場合は、これが必要になることがあります。

has_usable_password()

Returns False if set_unusable_password() has been called for this user.

get_session_auth_hash()

Returns an HMAC of the password field. Used for Session invalidation on password change.

You should also define a custom manager for your user model. If your user model defines username, email, is_staff, is_active, is_superuser, last_login, and date_joined fields the same as Django’s default user, you can just install Django’s UserManager; however, if your user model defines different fields, you’ll need to define a custom manager that extends BaseUserManager providing two additional methods:

class models.CustomUserManager

create_user(*username_field*, password=None, **other_fields)

The prototype of create_user() should accept the username field, plus all required fields as arguments. For example, if your user model uses email as the username field, and has date_of_birth as a required field, then create_user should be defined as:

def create_user(self, email, date_of_birth, password=None):
    # create user here
    ...

create_superuser(*username_field*, password, **other_fields)

The prototype of create_superuser() should accept the username field, plus all required fields as arguments. For example, if your user model uses email as the username field, and has date_of_birth as a required field, then create_superuser should be defined as:

def create_superuser(self, email, date_of_birth, password):
    # create superuser here
    ...

Unlike create_user(), create_superuser() must require the caller to provide a password.

BaseUserManager provides the following utility methods:

class models.BaseUserManager

classmethod normalize_email(email)

Normalizes email addresses by lowercasing the domain portion of the email address.

get_by_natural_key(username)

Retrieves a user instance using the contents of the field nominated by USERNAME_FIELD.

make_random_password(length=10, allowed_chars='abcdefghjkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ23456789')

Returns a random password with the given length and given string of allowed characters. Note that the default value of allowed_chars doesn’t contain letters that can cause user confusion, including:

• i, l, I, and 1 (lowercase letter i, lowercase letter L, uppercase letter i, and the number one)
• o, O, and 0 (lowercase letter o, uppercase letter o, and zero)

Extending Django’s default User

If you’re entirely happy with Django’s User model and you just want to add some additional profile information, you could simply subclass django.contrib.auth.models.AbstractUser and add your custom profile fields, although we’d recommend a separate model as described in the “Model design considerations” note of Specifying a custom user model. AbstractUser provides the full implementation of the default User as an abstract model.

Custom users and the built-in auth forms

Django’s built-in forms and views make certain assumptions about the user model that they are working with.

The following forms are compatible with any subclass of AbstractBaseUser:

• AuthenticationForm: Uses the username field specified by USERNAME_FIELD.
• SetPasswordForm
• PasswordChangeForm
• AdminPasswordChangeForm

The following forms make assumptions about the user model and can be used as-is if those assumptions are met:

• PasswordResetForm: Assumes that the user model has a field named email that can be used to identify the user and a boolean field named is_active to prevent password resets for inactive users.

Finally, the following forms are tied to User and need to be rewritten or extended to work with a custom user model:

• UserCreationForm
• UserChangeForm

If your custom user model is a simple subclass of AbstractUser, then you can extend these forms in this manner:

from django.contrib.auth.forms import UserCreationForm
from myapp.models import CustomUser

class CustomUserCreationForm(UserCreationForm):

    class Meta(UserCreationForm.Meta):
        model = CustomUser
        fields = UserCreationForm.Meta.fields + ('custom_field',)

Custom users and django.contrib.admin

If you want your custom user model to also work with the admin, your user model must define some additional attributes and methods. These methods allow the admin to control access of the user to admin content:

class models.CustomUser

is_staff

Returns True if the user is allowed to have access to the admin site.

is_active

Returns True if the user account is currently active.

has_perm(perm, obj=None):

Returns True if the user has the named permission. If obj is provided, the permission needs to be checked against a specific object instance.

has_module_perms(app_label):

Returns True if the user has permission to access models in the given app.

You will also need to register your custom user model with the admin. If your custom user model extends django.contrib.auth.models.AbstractUser, you can use Django’s existing django.contrib.auth.admin.UserAdmin class. However, if your user model extends AbstractBaseUser, you’ll need to define a custom ModelAdmin class. It may be possible to subclass the default django.contrib.auth.admin.UserAdmin; however, you’ll need to override any of the definitions that refer to fields on django.contrib.auth.models.AbstractUser that aren’t on your custom user class.

Custom users and permissions

To make it easy to include Django’s permission framework into your own user class, Django provides PermissionsMixin. This is an abstract model you can include in the class hierarchy for your user model, giving you all the methods and database fields necessary to support Django’s permission model.

PermissionsMixin provides the following methods and attributes:

class models.PermissionsMixin

is_superuser

真偽値です。明示的にアサインすることなく全てのパーミッションを持たせるかどうかを指定します。

get_group_permissions(obj=None)

ユーザがグループを通して持つパーミッションの文字列のセットを返します。

obj が渡されたとき、指定されたオブジェクトに対するグループパーミッションのみを返します。

get_all_permissions(obj=None)

ユーザがグループおよびユーザパーミッションを通して持つパーミッションの文字列のセットを返します。

obj が渡された場合、指定されたオブジェクトに対するパーミッションのみを返します。

has_perm(perm, obj=None)

Returns True if the user has the specified permission, where perm is in the format "<app label>.<permission codename>" (see permissions). If the user is inactive, this method will always return False.

obj が渡された場合、このメソッドは指定されたオブジェクトに対してパーミッションのチェックを行い、モデルに対しては行いません。

has_perms(perm_list, obj=None)

ユーザが指定されたそれぞれのパーミッションを持っている場合、True を返します。各パーミッションは "<app label>.<permission codename>" 形式です。ユーザが非アクティブの場合、このメソッドは常に False を返します。

obj が渡された場合、このメソッドは指定されたオブジェクトに対してパーミッションのチェックを行い、モデルに対しては行いません。

has_module_perms(package_name)

ユーザが指定されたパッケージ (Django のアプリケーションラベル)内の全パーミッションを持っている場合、True を返します。ユーザが非アクティブの場合、このメソッドは常に False を返します。

PermissionsMixin and ModelBackend

If you don’t include the PermissionsMixin, you must ensure you don’t invoke the permissions methods on ModelBackend. ModelBackend assumes that certain fields are available on your user model. If your user model doesn’t provide those fields, you’ll receive database errors when you check permissions.

Custom users and proxy models

One limitation of custom user models is that installing a custom user model will break any proxy model extending User. Proxy models must be based on a concrete base class; by defining a custom user model, you remove the ability of Django to reliably identify the base class.

If your project uses proxy models, you must either modify the proxy to extend the user model that’s in use in your project, or merge your proxy’s behavior into your User subclass.

A full example

Here is an example of an admin-compliant custom user app. This user model uses an email address as the username, and has a required date of birth; it provides no permission checking, beyond a simple admin flag on the user account. This model would be compatible with all the built-in auth forms and views, except for the user creation forms. This example illustrates how most of the components work together, but is not intended to be copied directly into projects for production use.

This code would all live in a models.py file for a custom authentication app:

from django.db import models
from django.contrib.auth.models import (
    BaseUserManager, AbstractBaseUser
)


class MyUserManager(BaseUserManager):
    def create_user(self, email, date_of_birth, password=None):
        """
        Creates and saves a User with the given email, date of
        birth and password.
        """
        if not email:
            raise ValueError('Users must have an email address')

        user = self.model(
            email=self.normalize_email(email),
            date_of_birth=date_of_birth,
        )

        user.set_password(password)
        user.save(using=self._db)
        return user

    def create_superuser(self, email, date_of_birth, password):
        """
        Creates and saves a superuser with the given email, date of
        birth and password.
        """
        user = self.create_user(
            email,
            password=password,
            date_of_birth=date_of_birth,
        )
        user.is_admin = True
        user.save(using=self._db)
        return user


class MyUser(AbstractBaseUser):
    email = models.EmailField(
        verbose_name='email address',
        max_length=255,
        unique=True,
    )
    date_of_birth = models.DateField()
    is_active = models.BooleanField(default=True)
    is_admin = models.BooleanField(default=False)

    objects = MyUserManager()

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['date_of_birth']

    def get_full_name(self):
        # The user is identified by their email address
        return self.email

    def get_short_name(self):
        # The user is identified by their email address
        return self.email

    def __str__(self):              # __unicode__ on Python 2
        return self.email

    def has_perm(self, perm, obj=None):
        "Does the user have a specific permission?"
        # Simplest possible answer: Yes, always
        return True

    def has_module_perms(self, app_label):
        "Does the user have permissions to view the app `app_label`?"
        # Simplest possible answer: Yes, always
        return True

    @property
    def is_staff(self):
        "Is the user a member of staff?"
        # Simplest possible answer: All admins are staff
        return self.is_admin

Then, to register this custom user model with Django’s admin, the following code would be required in the app’s admin.py file:

from django import forms
from django.contrib import admin
from django.contrib.auth.models import Group
from django.contrib.auth.admin import UserAdmin as BaseUserAdmin
from django.contrib.auth.forms import ReadOnlyPasswordHashField

from customauth.models import MyUser


class UserCreationForm(forms.ModelForm):
    """A form for creating new users. Includes all the required
    fields, plus a repeated password."""
    password1 = forms.CharField(label='Password', widget=forms.PasswordInput)
    password2 = forms.CharField(label='Password confirmation', widget=forms.PasswordInput)

    class Meta:
        model = MyUser
        fields = ('email', 'date_of_birth')

    def clean_password2(self):
        # Check that the two password entries match
        password1 = self.cleaned_data.get("password1")
        password2 = self.cleaned_data.get("password2")
        if password1 and password2 and password1 != password2:
            raise forms.ValidationError("Passwords don't match")
        return password2

    def save(self, commit=True):
        # Save the provided password in hashed format
        user = super(UserCreationForm, self).save(commit=False)
        user.set_password(self.cleaned_data["password1"])
        if commit:
            user.save()
        return user


class UserChangeForm(forms.ModelForm):
    """A form for updating users. Includes all the fields on
    the user, but replaces the password field with admin's
    password hash display field.
    """
    password = ReadOnlyPasswordHashField()

    class Meta:
        model = MyUser
        fields = ('email', 'password', 'date_of_birth', 'is_active', 'is_admin')

    def clean_password(self):
        # Regardless of what the user provides, return the initial value.
        # This is done here, rather than on the field, because the
        # field does not have access to the initial value
        return self.initial["password"]


class UserAdmin(BaseUserAdmin):
    # The forms to add and change user instances
    form = UserChangeForm
    add_form = UserCreationForm

    # The fields to be used in displaying the User model.
    # These override the definitions on the base UserAdmin
    # that reference specific fields on auth.User.
    list_display = ('email', 'date_of_birth', 'is_admin')
    list_filter = ('is_admin',)
    fieldsets = (
        (None, {'fields': ('email', 'password')}),
        ('Personal info', {'fields': ('date_of_birth',)}),
        ('Permissions', {'fields': ('is_admin',)}),
    )
    # add_fieldsets is not a standard ModelAdmin attribute. UserAdmin
    # overrides get_fieldsets to use this attribute when creating a user.
    add_fieldsets = (
        (None, {
            'classes': ('wide',),
            'fields': ('email', 'date_of_birth', 'password1', 'password2')}
        ),
    )
    search_fields = ('email',)
    ordering = ('email',)
    filter_horizontal = ()

# Now register the new UserAdmin...
admin.site.register(MyUser, UserAdmin)
# ... and, since we're not using Django's built-in permissions,
# unregister the Group model from admin.
admin.site.unregister(Group)

Finally, specify the custom model as the default user model for your project using the AUTH_USER_MODEL setting in your settings.py:

AUTH_USER_MODEL = 'customauth.MyUser'